Site Investigation Using 2D Resistivity Imaging to Detect Subsurface Cavities and Weak Zones at Mosul’s Stadium, North Iraq (A Case Study)

Karst voids were encountered during a stadium construction in Mosul city, NE Iraq. Drilling in the site showed the presence of cavities and zone of weak rocks in some boreholes. However, the boreholes show only a limited picture of the subsurface beneath the borehole only, while drilling in all the site is expensive and time consuming. Surface geophysical methods can successfully be applied to detecting and mapping cavities, fractures and other karst features. These methods provide in-situ measurements of the subsurface non-invasively and can therefore provide a dramatic increase in spatial and temporal coverage. A 2D resistivity imaging has been one of the most effective methods in this regard in that it often can provide a detailed picture of underground conditions without digging, and it lacks many of the limitations of other geophysical tools. The method was successfully applied in the proposed site of the Mosul Stadium Project, which gave very clear pictures of the cavities and weak rock zones in the subsurface.